Google plans to remove online certificate revocation checks from future versions of Chrome, because it considers the process inefficient and slow. Browsers currently check if a website's SSL certificate has been revoked by its issuing Certificate Authority (CA) when trying to establish an HTTPS connection.
These checks are done by querying CA-operated servers through a special protocol known as OCSP (Online Certificate Status Protocol).

The problem is that browsers can't always communicate with the validation servers because of various technical problems and when something like this happens, the HTTPS connections should not be established; at least in theory.